keeping datasets out of snapshots

[jknockaert]

On the Ubuntu 22.04 I read the suggestion to create separate datasets for /var/cache and others if you wish to separate these to exclude them from snapshots. Still the instruction creates these as System Datasets (e.g. rpool/ROOT/ubuntu_$UUID/var/cache), so I wondered if they are really excluded from snapshots. Shouldn't they rather be created as Persistent Datasets (e.g. rpool/var/cache) in order to keep them out of snapshots? Running zsysctl show --full seems to suggest in the History section of the output that all System Datasets (as well as all User Datasets) are included in snapshots...